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S Dunlap

Publications and source records attributed to S Dunlap.

9 recordsLinked to original sources
PubMed1992

Somatic cell mapping of T-cell receptor CD3 complex and CD8 genes in cattle.

Bovine genes encoding T-cell receptor, CD3, and CD8 molecules have been mapped to syntenic groups using bovine x rodent hybrid somatic cells. T-cell receptor alpha and delta chains were assigned to bovine syntenic group U5, and the beta and gamma genes were syntenic with each other and with markers on U13. CD3E and CD3D genes were syntenic with each other and located to bovine syntenic group U19. CD8 was most concordant with markers of syntenic group U16, although the concordancy was only 85% and the assignment must be regarded as tentative. The comparative gene maps of human chromosome 7, bovine syntenic group U13, and mouse chromosomes 6 and 13 suggest extensive evolutionary conservation.

Animals↗
PubMed1991

A simple and efficient method for purifying and quantifying schizonts from Theileria parva-infected cells.

An improved method for the purification of Theileria parva schizonts from infected bovine cells is described. The technique is simpler and more rapid than previously described methods and gives rise to greater yields of schizonts with negligible contamination by host-cell components. In addition, a fluorescent staining technique was developed whereby live schizonts purified from infected cells can be enumerated and sorted using the flow cytometer. An assessment of the quality of schizonts prepared according to our method as a source of RNA for the construction of parasite cDNA libraries suggests that RNA derived from these preparations is free of host nucleic acids.

Animals↗
PubMed1991

Cell surface phenotype of two cloned populations of bovine lymphocytes displaying non-specific cytotoxic activity.

Monoclonal antibodies specific for T cell differentiation antigens were tested on four cloned populations of lymphocytes derived from the peripheral blood mononuclear cells of an animal immunised with Theileria parva. The clones were defined functionally in terms of cytotoxic activity, MHC restriction and expression of messenger RNA for CD3 and T cell receptor (TCR). Two clones contained RNA transcripts for CD3, TCR-alpha and beta and were positive for CD2, CD5 and CD6; one of these was a typical CD4+ class II MHC-restricted non-cytotoxic clone while the other was a CD8+ class I MHC-restricted cytotoxic clone. By contrast, the remaining two clones had the characteristics of non-specific killer cells in that they exhibited moderate levels of non-MHC-restricted killing; they contained TCR-delta mRNA and a 1.2 kb truncated form of TCR-beta message, but they did not contain CD3 or TCR-alpha mRNA. One of these non-specific killer clones only expressed CD2 whereas the other clone only expressed CD8, but without the CD8 determinant recognised by monoclonal antibodies CC58 and BAT52. All four clones were negative for the WC1 antigen which is expressed on gamma/delta T lymphocytes.

Animals↗
PubMed1991

Influence of calcium administration on the short-term hemodynamic and anti-ischemic effects of nifedipine.

This prospective study investigated whether pretreatment with intravenously administered calcium would influence the effect of nifedipine on rest hemodynamics and treadmill performance in patients with ischemic heart disease. Seventeen patients were studied after undergoing a qualifying treadmill exercise test that revealed ST segment depression indicative of ischemic heart disease. Study subjects performed three additional treadmill tests as part of the protocol. One treadmill test was obtained from each patient to provide baseline measurements without a preceding intravenous infusion and in the absence of all antianginal drugs including nifedipine; two additional exercise tests were preceded by an infusion and 10 mg of bite-and-swallow nifedipine. The infusions, administered in a randomized, double-blind, crossover fashion, consisted of either 10 ml of 10% calcium chloride (13.6 mEq) in 50 ml of 5% dextrose in water or 5% dextrose in water alone. Rest systolic blood pressure (134 +/- 4.6 mm Hg) was unchanged after placebo infusion (135 +/- 4.6 mm Hg) but decreased to 124 +/- 4.1 mm Hg (p less than 0.01) 25 min after nifedipine administration. Rest systolic blood pressure increased after calcium infusion (from 139 +/- 4.3 to 148 +/- 4.8 mm Hg, p less than 0.01) and then decreased significantly 25 min after nifedipine administration to 135 +/- 4.2 mm Hg (p less than 0.01). Despite a decrease at the time of peak nifedipine effect after either infusion, systolic blood pressure was significantly lower after administration of nifedipine alone than after administration of calcium and nifedipine (124 +/- 4.1 vs. 135 +/- 4.2 mm Hg, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1990

Identification of a bovine surface antigen uniquely expressed on CD4-CD8- T cell receptor gamma/delta+ T lymphocytes.

In this study, two monoclonal antibodies, IL-A29 and CC15, are described that identify a novel bovine cell surface marker of 215/300 kDa. The antibodies reacted with a discrete population of resting lymphocytes in peripheral blood which, in young animals, constituted about 25% of the mononuclear cells. Thymus, lymph nodes and spleen contained less than 5% positive cells. These cells were negative for surface Ig, a monocyte/granulocyte marker, and the T lymphocyte antigens CD2, CD6, CD4 and CD8. Immunohistological analyses revealed the presence of IL-A29/CC15-positive lymphocytes in the thymic medulla, in the outer cortex of lymph nodes, in the marginal zones of the spleen, in the dermal and epidermal layers of the skin and in the lamina propria of the gut. The IL-A29/CC15+ cells in unfractionated blood mononuclear cells responded in autologous and allogeneic mixed lymphocyte cultures, and when purified they responded to concanavalin A in the presence of recombinant interleukin 2. These observations suggested this population of cells belonged to the T cell lineage. In order to unambiguously define their lineage, cDNA clones encoding bovine T cell receptor (TcR) and CD3 proteins were isolated. Northern blot analyses of IL-A29/CC15+ cell populations and of established cell lines of various lineages demonstrated that they expressed TcR delta and CD3 gamma, delta and epsilon mRNA: TcR alpha was not expressed, whereas only a truncated form of TcR beta mRNA was present. These results indicate that the IL-A29 and CC15 antibodies define a unique population of CD4-CD8-, gamma/delta T cells.

Animals↗
PubMed1989

An enhancer located in a CpG-island 3' to the TCR/CD3-epsilon gene confers T lymphocyte-specificity to its promoter.

The gene encoding the CD3-epsilon chain of the T cell receptor (TCR/CD3) complex is uniquely transcribed in all T lymphocyte lineage cells. The human CD3-epsilon gene, when introduced into the mouse germ line, was expressed in correct tissue-specific fashion. The gene was then screened for T lymphocyte-specific cis-acting elements in transient chloramphenicol transferase assays. The promoter (-228 to +100) functioned irrespective of cell type. A 1225 bp enhancer with strict T cell-specificity was found in a DNase I hypersensitive site downstream of the last exon, 12 kb from the promoter. This site was present in T cells only. The CD3-epsilon enhancer did not display sequence similarity with the T cell-specific enhancer of CD3-delta, a related gene co-regulated with CD3-epsilon during intrathymic differentiation. The CD3-epsilon enhancer was unusual in that it constituted a CpG island, and was hypomethylated independent of tissue type. Two HTLV I-transformed T cell lines were identified in which the CD3-epsilon gene was not expressed, and in which the enhancer was inactive.

Animals↗
PubMed1977

Infective endocarditis: a current review.

Infective endocarditis is a dynamic disease for which various infective organisms may be responsible in different patient populations. Antimicrobial therapy should be directed against the specific organism after it has been identified by blood culture. An agent with a spectrum that includes the enterococci should be given in the meantime. Prophylactic use of a bactericidal agent is necessary for patients with valvular or congenital heart disease. Recent advances in microbiologic and cardiac diagnostic procedures offer the clinician various methods of following the activity of the disease, and immunobiology has provided new insights into its pathogenesis.

Endocarditis, Bacterial↗